1. Field of the Invention
The present invention relates to a video signal recording and/or reproducing method and video signal recording and/or reproducing apparatus. More particularly, the invention relates to a video signal recording and/or reproducing method and video signal recording and/or reproducing apparatus for recording a digital video signal of baseband on a disk unit including multiple disk recording mediums and reading the recorded video signal out of the disk recording mediums, wherein in case a pixel cannot be read out as a video signal, the video signal for the pixel is produced based on the interpolation process using video signals of the neighboring pixels so that a high-fidelity picture is reproduced continuously.
2. Description of the Prior Art
With the recent prevalence of multi-channel information providing services including the CATV (cable television), there is a growing demand for recording or reproducing multiple video/audio data simultaneously or recording one video/audio data while reproducing another video/audio data with one video/audio data recording and/or reproducing apparatus, which is different from the usage of the conventional VTR (video tape recorder). In order to meet this demand, an apparatus called video server (or AV (audio and/or video) server) which records and reproduces video/audio signals on a random-access recording medium such as a hard disk is going to prevail.
In general, the video server used in broadcast stations needs to have a high data transfer rate to meet the demand of high image and sound quality and a large recording capacity for long-time data recording. On this account, there is an attempt of raising the data transfer rate and increasing the recording capacity by employment of a data recording and/or reproducing apparatus including multiple hard disks (will be termed xe2x80x9cHDsxe2x80x9d) which can store video/audio data and process the data in parallel, and another attempt of enhancing the reliability of HDs against the failure of HD based on the recording of parity data. With these schemes put into practice, it becomes possible to accomplish a versatile multi-channel video server which reproduces multi-channel data simultaneously based on the discrete recording of source video/audio data, or build a VOD (video on-demand) or NVOD (near video on-demand) system based on the multi-channel, time-shift reproduction of one source data, even in case the number of channels required varies depending on the program or the mode of broadcasting.
The data recording and/or reproducing apparatus used for the above-mentioned video server is based on the RAID (Redundant Arrays of Inexpensive Disks) technique which uses hard disk drive units (will be termed xe2x80x9cHDDsxe2x80x9d) including multiple HDs, as proposed by Patterson, et al. in 1988 in the article entitled xe2x80x9cA Case for Redundant Arrays of Inexpensive Disks (RAID)xe2x80x9d in the publication of ACM SIGMOND Conference, Chicago, Ill., Jun. 1-3, 1988.
The RAID described in the above-mentioned article falls into RAID-1 through RAID-5. The RAID-1 is a scheme of writing the same content onto two HDDs. The RAID-3 is a scheme of dividing input data into pieces of data of a certain length and recording the data onto multiple HDDs, and producing parity data which is the exclusive logical sum of corresponding data blocks of the HDDs and recording the parity data onto another HDD. The RAID-5 is a scheme of recording one large divided data block onto one HDD and recording a block of parity data which is the exclusive logical sum of corresponding data blocks of the HDDs distributively onto other HDDs.
However, even the data recording and/or reproducing apparatus arranged as described above cannot correct the reproduced data if two or more of the HDDs which form the RAIDs fail to read out data simultaneously or if the RAIDs in parallel operation quit the data readout function.
The probability of the occurrence of simultaneous read error of two or more RAIDs is extremely low theoretically, and it is conceived to impose no problem so far as the above-mentioned video server which records and reproduces data by means of multiple RAIDs is kept used in broadcast stations or the like.
Practically, however, quitting of function of RAIDs due to a defect in the RAID control program or the simultaneous failure of two or more HDDs due to the disparity of products at the early stage of HDD manufacturing can possibly occur at a frequency beyond the theoretical rate.
The failure of normal readout of video and audio data from the RAIDs will compel the broadcast station to suspend the broadcasting or editing of a program in the course of broadcasting for example.
Accordingly, it is an object of the present invention to provide a data recording apparatus, data reproduction apparatus, data recording and/or reproducing apparatus, a data recording method, data reproduction method, and data recording and/or reproducing method capable of reproducing high-fidelity data continuously from nonlinear-access recording mediums even in case data cannot be read out partially.
A data recording apparatus according to a first aspect of this invention for recording data including video data onto a plurality of nonlinear-access recording mediums comprises: a plurality of input and/or output processing means which operate in the time slots assigned thereto to release data, which has been supplied from the outside, to the recording mediums so that the data is recorded onto the recording mediums, and operate in the assigned time slots to process the data recorded on the recording mediums and release the data to the outside; and recording control means which controls the data of individual pixels released by the input and/or output processing means such that data of neighboring pixels are recorded onto different ones of the recording mediums.
A data recording apparatus according to a second aspect of this invention for recording data including video data onto a plurality of nonlinear-access recording mediums comprises: a plurality of data input processors which operate in the time slots assigned thereto to release data, which has been supplied from the outside, to the recording mediums so that the data is recorded onto the recording mediums; and recording means which records the data released by the data input processors onto the recording mediums, with the data input processors each including first serial-to-parallel conversion means which converts the input pixel data into parallel pixel data, and with the recording means including second serial-to-parallel conversion means which converts the parallel pixel data released by the data input processor into parallel pixel data.
A data reproduction apparatus according to a third aspect of this invention for reproducing data including video data which is recorded on a plurality of nonlinear-access recording mediums such that data of neighboring image pixels are recorded on different recording mediums comprises: a plurality of output processing means which operate in the time slots assigned thereto to release data including video data recorded on the recording mediums to the outside, with the output processing means including error correction processing means which implements the error correction based on an interpolation process using data of the neighboring pixels among the data reproduced from the recording mediums.
A data reproduction apparatus according to a fourth aspect of this invention for reproducing data including video data which is recorded on a plurality of nonlinear-access recording mediums such that data of neighboring image pixels are recorded on different recording mediums comprises: a plurality of reproduction means which reproduce the data recorded on the recording mediums; and a plurality of output processing means which operate in the time slots assigned thereto to process the data released by the reproduction means and release the processed data to the outside, with the reproduction means each including first parallel-to-serial conversion means which converts the data released from the recording mediums into serial data, and with the output processing means each including second parallel-to-serial conversion means which converts the serial pixel data released by the reproduction means into serial pixel data and error correction processing means which implements the error correction based on an interpolation process using data of the neighboring pixels among the data released by the second parallel-to-serial conversion means.
A data reproduction apparatus according to a fifth aspect of this invention for reproducing data including video data which is recorded on a plurality of nonlinear-access recording mediums such that data of neighboring image pixels are recorded on different recording mediums comprises: a plurality of output processing means which operate in the time slots assigned thereto to release the data reproduced from the recording mediums to the outside, with the output processing means each including function quit detection means which receives a detection signal indicative of whether or not data is released from the nonlinear-access recording mediums and responds to the detection signal, which indicates that the data is not released, to release specific error detection data in substitution for the data from the recording mediums and error correction processing means which implements the error correction process for the error detection data released by the function quit detection means based on an interpolation process using reproduced data of the neighboring pixels.
A data reproduction apparatus according to a sixth aspect of this invention for reproducing data including video data which is recorded on a plurality of nonlinear-access recording mediums such that data of neighboring image pixels are recorded on different recording mediums comprises: a plurality of reproduction means which reproduce the recorded data; and a plurality of output processing means which operate in the time slots assigned thereto to release the data reproduced from the recording mediums to the outside, with the reproduction means each including error detection means which receives and responds to the error detection signal, which indicates that data cannot be read out of the nonlinear-access recording mediums, to release error detection data in substitution for the data from the recording mediums, and with the output processing means each including error correction processing means which implements the error correction process for the error detection data released by the reproduction means based on an interpolation process using data of the neighboring pixels released by the reproduction means.
A data reproduction apparatus according to a seventh aspect of this invention for reproducing data including video data which is recorded on a plurality of nonlinear-access recording mediums such that data of neighboring image pixels are recorded on different recording mediums comprises: reproduction means which reproduces the recorded data; and output processing means which operates in the time slot assigned thereto to release the data released by the reproduction means to the outside, with the reproduction means including parity calculation means which receives the data read out of the recording mediums and responds to the occurrence of readout error of the data to implement the parity calculation for the data read out of the other recording mediums by using the parity data and detect the error of the parity data and parity error detection means which receives the readout data and receives and responds to the parity error detection signal from the parity calculation means to release specific error detection data in substitution for all of the readout data, and with the output processing means including error correction processing means which implements the error correction process for the error detection data released by the reproduction means using data of the neighboring pixels released by the reproduction means.
A data recording and/or reproducing apparatus according to an eighth aspect of this invention for recording data including video data onto a plurality of nonlinear-access recording mediums and reproducing the recorded data is the combination of the data recording apparatus of the first aspect and the data reproduction apparatus of the third aspect.
A data recording and/or reproducing apparatus according to a ninth aspect of this invention for recording data including video data onto a plurality of nonlinear-access recording mediums and reproducing the recorded data is the combination of the data recording apparatus of the first aspect and the data reproduction apparatus of the fifth aspect.
A data recording and/or reproducing apparatus according to a tenth aspect of this invention for recording data including video data onto a plurality of nonlinear-access recording mediums and reproducing the recorded data is the combination of the data recording apparatus of the first aspect and the data reproduction apparatus of the sixth aspect.
A data recording and/or reproducing apparatus according to a eleventh aspect of this invention for recording data including video data onto a plurality of nonlinear-access recording mediums and reproducing the recorded data is the combination of the data recording apparatus of the first aspect and the data reproduction apparatus of the seventh aspect.
A data recording and/or reproducing apparatus according to a twelfth aspect of this invention for recording data including video data onto a plurality of nonlinear-access recording mediums and reproducing the recorded data is the combination of the data recording apparatus of the second aspect and the data reproduction apparatus of the fourth aspect.
A data recording method according to the first aspect of this invention for recording data including video data onto a plurality of nonlinear-access recording mediums comprises: a first step of operating in the assigned time slot to release data which has been supplied from the outside so that the data is recorded onto the recording mediums; and a second step of controlling the data of individual image pixels released in the first step such that data of neighboring pixels are recorded onto different ones of the recording mediums.
A data recording method according to the second aspect of this invention for recording data including video data onto a plurality of nonlinear-access recording mediums comprises: a first step of operating in the assigned time slots to release data, which has been supplied from the outside, to the recording mediums so that the data is recorded onto the recording mediums; and a second step of recording the data released in the first step onto the recording mediums, with the first step including a first serial-to-parallel conversion step of converting the input pixel data into parallel data, and with the second step including a second serial-to-parallel conversion step of converting the parallel pixel data released in the first conversion step into parallel data.
A data reproduction method according to the third aspect of this invention for reproducing data including video data which is recorded on a plurality of nonlinear-access recording mediums comprises: an output processing step of operating in the assigned time slot to release data including video data recorded on the recording mediums to the outside, with the output processing step including an error correction processing step of implementing the error correction based on an interpolation process using data of the neighboring pixels among the data reproduced from the recording mediums.
A data reproduction method according to the fourth aspect of this invention for reproducing data including video data which is recorded on a plurality of nonlinear-access recording mediums such that data of neighboring image pixels are recorded on different recording mediums comprises: a first step of reproducing the data recorded on the recording mediums; and a second step of operating in the assigned time slot to process the data reproduced in the first step and release the processed data to the outside, with the first step including a first parallel-to-serial conversion step of converting the data released from the recording mediums into serial data, and with the second step including a second parallel-to-serial conversion step of converting the serial data released in the first conversion step into serial data and an error correction step of implementing the error correction based on an interpolation process using data of the neighboring pixels among the data released in the second conversion step.
A data reproduction method according to the fifth aspect of this invention for reproducing data including video data which is recorded on a plurality of nonlinear-access recording mediums such that data of neighboring image pixels are recorded on different recording mediums comprises: a first step of operating in the assigned time slot to release the data reproduced from the recording mediums to the outside, with the first step including a function quit detection step of receiving a detection signal indicative of whether or not data is released from the nonlinear-access recording mediums and responding to the detection signal, which indicates that the data is not released, to release specific error detection data in substitution for the data from the recording mediums and an error correction processing step of implementing the error correction process for the error detection data produced in the function quit detection step based on an interpolation process using reproduced data of the neighboring pixels.
A data reproduction method according to the sixth aspect of this invention for reproducing data including video data which is recorded on a plurality of nonlinear-access recording mediums such that data of neighboring image pixels are recorded on different recording mediums comprises: a first step of reproducing the recorded data; and a second step of operating in the assigned time slot to release the data reproduced from the recording mediums to the outside, with the first step including an error detection step of receiving and responding to the error detection signal, which indicates that data cannot be read out of the nonlinear-access recording mediums, to release error detection data in substitution for the data from the recording mediums, and with the second step including an error correction processing step of implementing the error correction process for the error detection data produced in the first step based on an interpolation process using data of the neighboring pixels released in the first step.
A data reproduction method according to the seventh aspect of this invention for reproducing data including video data which is recorded on a plurality of nonlinear-access recording mediums such that data of neighboring image pixels are recorded on different recording mediums, with at least one of the nonlinear-access recording mediums being assigned to record parity data of data which is recorded on the other recording mediums, comprises: a first step of reproducing the recorded data; and a second step of operating in the assigned time slot to release the data released in the first step to the outside, with the first step including a parity calculation step of receiving the data read out of the recording mediums and responding to the occurrence of readout error of the data to implement the parity calculation for the data read out of the other recording mediums by using the parity data and detect the error of the parity data and a parity error detection step of receiving the readout data and receiving and responding to the parity error detection signal produced in the parity calculation step to release specific error detection data in substitution for all of the readout data, and with the second step including an error correction processing step of implementing the error correction process for the error detection data produced in the first step by using data of the neighboring pixels reproduced in the first step.
A data recording and/or reproducing method according to an eighth aspect of this invention for recording data including video data onto a plurality of nonlinear-access recording mediums and reproducing the recorded data is the combination of the data recording method of the first aspect and the data reproduction method of the third aspect.
A data recording and/or reproducing method according to a ninth aspect of this invention for recording data including video data onto a plurality of nonlinear-access recording mediums and reproducing the recorded data is the combination of the data recording method of the first aspect and the data reproduction method of the fifth aspect.
A data recording and/or reproducing method according to a tenth aspect of this invention for recording data including video data onto a plurality of nonlinear-access recording mediums and reproducing the recorded data is the combination of the data recording method of the first aspect and the data reproduction method of the sixth aspect.
A data recording and/or reproducing method according to a eleventh aspect of this invention for recording data including video data onto a plurality of nonlinear-access recording mediums and reproducing the recorded data is the combination of the data recording method of the first aspect and the data reproduction method of the seventh aspect.
A data recording and/or reproducing method according to a twelfth aspect of this invention for recording data including video data onto a plurality of nonlinear-access recording mediums and reproducing the recorded data is the combination of the data recording method of the second aspect and the data reproduction method of the fourth aspect.